1. Technical Field
The present invention relates generally to a battery powered device with dynamic power and performance management abilities; and, more specifically, to a battery powered device which dynamically adjusts voltage supply levels and processing speed to maximize battery life while still achieving optimum processing performance when called upon. The present invention also relates to temperature sensing control which, when necessary, overrides the power and performance management functionality to cause operation at desired temperatures
2. Related Art
Portable computing devices continue to provide ever increasing performance and functionality. With increases in performance, such computing devices place increased load requirements on their battery power supplies. Due to size and space concerns, however, batteries of increased size and weight, which could service the increased performance of the portable computing devices with additional capacity, are generally not a viable option for the portable computing devices.
Thus, attempts have been made to reduce battery power consumption in portable devices. For example, clocking frequencies are often reduced to reduce the energy consumption of affected circuitry. However, at reducing clocking frequencies, the performance of processing units within the portable devices is degraded. Similar techniques place the portable devices in a non-operational or idle state when usage allows for such. However, when recovering from the non-operational or idle states, noticeable delays in performance result. Further, many portable devices require a minimal level of performance at all times.
Another power conservation technique involves reducing operating supply voltages. Because operation at lower voltages tends to decrease power consumption, much of the hardware in portable devices is designed to operate at relatively lower operating supply voltage levels, typically 3.3 volts or less. Limitations on operating speeds at such lower voltage supply levels, however, generally require operation at lower clocking frequencies, thus resulting in reduced performance.
In order to achieve an increase performance in portable devices, operating frequencies must typically be increased, thereby increasing the amount of power consumed and, resultantly, the amount of heat generated. In general, for a capacitive load, the relationship between the power generated by an electronic device and the operational supply voltage and frequency is given by:P=αV2·Fwhere P is the power generated, a is a constant, v is the operational voltage and F is the operational frequency. Therefore, with increased operational frequencies, it is desirable to correspondingly decrease the operational voltage in order to minimize the power consumed and the heat generated by the electronic device. However, the dichotomy of decreasing the operational voltage of an electronic device operating at high frequencies is that the switching speeds of electronic devices operating at lower voltages are slowed as a result of the lower voltages. Thus, it is difficult to obtain high frequency operation of an electronic device with simultaneous low power operation.
Thus, there lies a need for a system that optimizes the operation of a portable device to optimize performance while simultaneously working to extend battery life. Further, there lies a need for such a portable device that operates in a desired operating range so as to avoid heat related failures.